What is the purpose of the other associated subunits attached to the alpha subunit in the Ca2+ channel?

Which activates faster - Ca2+ or Na2+ channels?

Na2+ channels are much faster than Ca2+ channels.

6

How can snail neurones be used to show that Ca2+ is responsible for Ca2+ channel inactivation?

Snails have Ba2+ as well, which will pass through Ca2+ channels instead of Ca2+. When it does this, much less inactivation of channels is seen, so it must be increased intracellular [Ca2+] that leads to inactivation of Ca2+ channels

7

What are motor end plates?

The point at which the axon connects to the myofibres

8

What are snare proteins?

These form snare complexes are direct neurontransmitter to be released. They do this by bringing the vesicles close to the membrane and forming a "fusion pore", through which neurotransmitter is released.

9

How many molecules of ACh must bind to nicotinic ACh receptors to make them open?

2

10

Which ions are allowed through nACh receptors?

Na+ is allowed in, and K+ is allowed out.

11

What happens to a muscle action potential once it reaches an end plate?

It is initiated adjacent to the end-plate and propagates along the muscle fibre, initiating contraction of the skeletal muscle fibre.